Lubricating oils



Patented Mar. 10, 1936 g UNITED STATES mnmca'rmc oms Anderson W. Balatonand Carl W. Christensen,

Chicago, Ill., assignors to Armour and Company, Chicago, 111., acorporation of Illinois No Drawing. Application May 4, 1935,

Serial No. 19,906

9Claims. (c1. s x-s) This invention relates to lubricating oils and itcomprises an improved lubricating oil composed of a hydrocarbonlubricating oil to which has been added a mixed ketone in quantities ofthe order of 0.1 to 1 percent.

Within recent years eflorts have been made to improve minerallubricating oils by adding various ingredients thereto. In many casessuch additions have been made for the purpose of improving thatcharacteristic of the oil commonly referred to as oiliness. These addedsubstances have mostly been fatty acids such as oleic acid, variousglycerides, lard, and the like. The property of oiliness has not beenclearly defined, but the term has a rather definite meaning to thoseskilled in the art. Some have defined it as that property which an oilmust possess to a sufiicient degree to enable the oil to lubricateadequately under all conditions of use. In more practical terms, an oilyoil is one which will forma film between bearing surfaces of suchstrength that the film will withstand rupture under extreme conditionsof pressure or temperature. To put it another way, an oily oil is onewhich has high film strength and as a result will give better engineperformance under all conditions of use. At'the same time, however, suchoils should have low internal friction and should also have the propertyof clinging tometal surfaces. It used to be considered that viscositywas a good criterion of the oiliness in oil 0 higher the viscosity thestronger would be the oil film. However, it has now been pretty wellacknowledged that viscosity alone does not explain oiliness in an oil.

As stated, the prior art has hitherto ,added small quantities ofvegetable oils such as oleic acid to hydrocarbon lubricating oils.Undoubtedly such additions have proved beneficial, in

part because of the high "polar" characteristics of the higherfattyacids. That is to say. the carboxyllc acidgroup of the fatty acid tendsto cling to the'metal surfaces of a bearing and thus aids in thedevelopment of a persistent film.

5 However, in many instances, the internal friction of the compoundedoil has been increased and this .is a distinct disadvantage. Many oi theadded substances hitherto used increase the viscosity of the oil andhence such oils necessarily cause increased power losses in engineslubricated with them. This is because of the internal friction in theoil itself.

Another serious objection to the addition or substances like oleic acidand fats is that these added substances do not have very much resistanceto high temperatures. In a gasoline engine the crank-case temperaturemay on the average be about 210 F. and bearing temperatures may run ashigh as 400 F. Bearing pressures may o occasionally be as high as 600pounds per square n the theory that the inch which means that asatisfactory oil must have high film strength and heat resistance if itis to function continuously under these conditions. 1

Substances like oleic acid are notsufiiciently 5 heat resistant tooperate satisfactorily over long periods of time at the relatively hightemperatures in a rapidly rotating bearing. These substances, althoughthey initially contribute oiliness to an oil, tend to break down anddecompose at 10 high temperatures. This action may beoxidizing, or itmay in part be instituted by the presence of traces of moisture. Fattyesters are readily hydrolyzed at the high operating temperatures in thepresence of moisture and free 15 fatty acids thus liberated tend todecompose. All ofwhich means that such substances, althoughthey mayinitially improve a mineral lubricant very soon lose their effectivenessand actually prove detrimental. 20

' We have now discovered a-class of substances which can be addedtomineral lubricating oils in small amounts, of the order of 0.1 to 1percent, and which markedly improve the oiliness of the oil but do nothave the many disadvan- 25 tages unavoidably present in substanceshitherto suggested. We have discovered that compounds known as "mixedketones satisfy the require ments in this art. These mixed ketones canbe generically described-as ketones in which aryl 30 or heterocyclicgroups, and alkyl groups are linked to a carbonyl. -'And we have furtherdis covered that of the many substances which can be designated as mixedketones we find that those in which the alkyl group contains eleven 5 ormore carbon atoms are best. In our invention aryl or heterocyclicgroupsmay be varied over a wide range as will be described. Structurallythen, the compounds we add to a mineral lubricant oil can be genericallyillustrated as 40 wherein R is a ring compound either of the car-'bocyclic or heterocyclic series and R. is an alkyl .in lubrication. Wefind that ,.they contribute oiliness to a high degree and thus functionto 55 maintain high film strength under all conditions of pressure.

Moreover the compounds of our invention have a. beneficial efiectonviscosity. Many compounds hitherto added to mineral lubricating oils 00In.contrast thereto many of the compounds which we add to a lubricatingoil raise the viscosity index several points. For example. stearophenoneis one very advantageous substancetoaddtoanoilinthepracticeoi'ourinvention.Whenweaddlpercentoistearophenonetoa number 30 (SAE) Mid-Continentlubricating oil the viscosity index is increased from 86.7 to 92. At 100F. the viscosity (Saybolt) is 493 seconds whereas the untreated oil hasa viscosity of 514 seconds. At 210 F. both the compounded oil and theuntreated oil have the same viscosity.

Hence it is apparent that the addition of the aralkyl ketone hasdecreased the viscosity at 100 F. and thus increased the viscosityindex. This is a marked advantage because it means that oilines isincreased without increasing the internal iriction in the 011. As statedalmost all substances hitherto added to oils for increasing oilinesshave increased internal friction whereas, in our invention, the internalfriction is either decreased or remains substantially unchanged. Such aresult has long been desired.

In addition, many 01' the substances which we use for increasingoiliness pronouncedly lower the cloud point of the mineral lubricatingoil. In the example given above the original oil has a cloud point of 52F. The addition 01' 0.1 percent oi. stearophenone lowers the cloud pointto 30 F..

We shall now describe numerous examples oi compounds falling within thegeneric disclosure given above. It .is tobe understood 0! course thatthese compounds are simply admixed and blended in the minerallubricating oil in proportion of from about 0.1 to 1 percent based onthe weight of the oil. This quantity can be increased somewhat but to nosubstantial advantage. All or the compounds we add are. of course,soluble in lubricating oil, and it is to be understood that we can treatlubricating oils from any source and 01' any viscosity. We can add ourimproving substances to mixed lubricating oils and to lubricating oilscomposed oi. both mineral and vegetable oils such as castor oil, but inthe ordinary practice of our invention the ketones are generally addedto an ordinary mineral lubricating oil. We do not however wish to berestricted to lubricants composed entirely of mineral oils.

We shall now describe our invention with relerence to the treatment of aMid-Continent lubricating oil having an (SAE) viscosity of 30 it beingunderstood however that this is merely illustrative and not limiting.

There are many mixed ketones we can use. It the generic formula for ourcompolmds be written as R can be any alkyl group having eleven or morecarbon atoms. It can also be a substituted alkyl group. Thus R can beundecyl CuHn, tridecyl CnHrr, pentadecyl 01031:. and heptacecyl C11HJs.

R can be any one of a number of closed ring radicals. The following areexamples thereof; phenyl, xyiyi, tolyi, anisyl and chlorphenyl, thesebeing typical examples of phenyl and substituted phenyl radicals. R canalso be phenoxyphenyl, diphenyl, naphthyl and anthracyl or substitutionproducts thereof, as further examples of carbocylic ring compounds. Rcan also be Iuryi, fluoryl, carbazoyl, dibenzoturyl, thiophenyl anddibenzothiophenyl, as examples of heterocyclic radicals.

We shall now give examples of many compounds ialiing under our genericinvention.

In the following table, from 0.1 to 1 percent of various aralkyl ketonesare added to a No. 30 Mid-Continent lubricating oil which has a cloudpoint of 52 F., a pour point of 20 F. a Saybolt viscosity at F. oi 514seconds and at 210' I". 01 62 seconds, and a viscosity index of 86.7.

Table 1 v Ho o vkcoaisti mt Cloud Pour m vim-n was Mm point point mm 'r.'r'. .1 12 10 m 04 000 .0 u so 000 04 0a: 1.0 so so 400 00 01o .1 as 10no 01 014 .s :2 1s m 01 an 1.0 a0 :0 400 0: 00.0 .1 a an s11 00 01.1 .0so 10 000 02 an 1.0 a so 400 00 no .1 10 Y 10 m 0: 001 .o :0 10 m 02 as:1.0 40 as 100 01 on .1 11 so 114 01 01.0 .0 u 10 000 a 00.0 1.0 as 11000 0: 0110 .1 n 10 on 00 04.0 .0 11m -u m 02 00.0

dark 1.0 T00 --10 no 0: 01.0

dark .1 s4 10 on as 01.4 .0 :0 10 000 02 00.1 1.0 :0 :0 m 01 00.1 .1 0010 us 01 au .1 u 10 an as 00.1 1.0 u 10 001 01 00.0 .1 a a 00 as: .0 asan 010 01 01.0 1.0 no :0 00s a. as: .1 I4 ll Ill 03, n0 .0 a 10 000 nas: 1.0 ---..do a 0 40s 0: no CcatnHtah-alkfiwmphbd) Is a m 00 00.1

' One of the best ketonic substances to add is that aosaus The compoundfrom dimethyl aniline and stearoyl chloride is probably a mixture ofketones which can be generically described as dimethyl aminophenylheptadecyl ketones. The aralkyl phenones (lard fatty acids) were made byreacting acid chlorides obtained from lard fatty acids with benzene inthe presence of aluminum chloride as will be explained. It is a mixtureof ketones in which oleyl phenone probably predominates. Anthracylheptadecyl ketone colors the oil somewhat when used in percentages of0.5 and 1.0 which makes the cloud pointdetermination diflicult. Theseamounts do not however deleteriously affect oiliness and they actuallyreduce the pour point markedly.

Itis to be noted that most of the above compounds tabulated increase theviscosity index. In some instances the index is slightly reduced but thereduction is markedly less than that commonly met with when adding manyof the substances hitherto used for increasing oiliness.

It is of course obvious that we can use mixtures of ketones and thusobtain the desirable advantages of individual substances. For exam- Ipie we can add a mixture of phenyl heptadecyl ketone and anthracylheptadecyl ketone in this way obtaining the advantageous increase inviscosity index contributed by phenyl heptadecyl and the markedreduction in pour point contributed by anthracyl heptadecyl' ketone.Both of these compounds markedly increase oiliness in the oils. 1

Curiously, in some instances, impure ketones work better. This may bedue to the fact that the impure ketone really contains a mixture ofketonic compounds and this effect is especially noticeable in the case'of the anthracyl ketones.

obtained from reacting anthracene oil or fractions thereof with higherfatty acid chlorides by the Friedel-Crafts synthesis as will beexplained.

This gives us a mixture of ketones which arev difficult to isolateseparately but which markedly contribute oiliness to the lubricatingoil.

In Table 2 which follows we describe the effect of adding various othermixed ketones among which are ketones in which the alkyl radical isundecyl. This table also shows the effect of ketones inwhich the arylgroup is substituted by chlorine and by methoxy. The character of thelubricating oil treated is indicated at the bottom of the table. It wasa Number 30 Mid-Con- In the above table, cloudpoints and pour pointswere not determined in every instance. In the case of dibenzofurylheptadecyl ketone it is to be noted that 0.5 percent thereof lowers theviscosity index somewhat. When using this substance we therefore find itbest to keep the quantity at about 0.1 percent. Many of the ketonesgiven above are not ordinarily used in the commercial. practice of ourinvention because they are more expensive than substances likestearophenone and the anthracyl derivatives, but we have described thesecompounds to illustrate the generic characteristics of our invention.

Many of these mixed ketones or aralkyl ketones are new materials and, incopending applications, we have so claimed them as new compounds. All ofthese aralkyl ketones can be made by a simple Friedel-Crafts synthesis.This can be illustrated inconnection with the preparation of diphenyltridecyl ketone. Thirty-five grams of diphenyl are admixed with fiftygrams of myristyl chloride and 100 cubic centimeters of carbon disul-gefide. This mixture is cooled in an ice bath and then to it fifty gramsof aluminum chloride are slowly added with stirring untiLthere is nofurther evolution of hydrochloric acid. Then dilute hydrochloric acidsolution is added and the contents of the mixture steam-distilled. Thisremoves disulflde. The ketone can then be decanted from the aqueoussolution of aluminum chloride and crystallized from carbontetrachloride.

All of the many aralkyl ketones described herein can be made by thisgeneral procedure as w be apparent to those skilled in the art.

Thus when we wish to make the correspond-,- ing anthracyl compound westart with anthracyl or fractions of anthracyl oil. When we wish tomakethe corresponding furyl compound we start with furane.

In the appended claims we generically define radicals of the carbocyclicseries and heterocyclic series, as closed ring radicals, and wegenerically define our alkyl radicals as those comprising the alkylresidue of a fatty .acid containing at least twelve carbon atoms. Toillustrate, CrzHasCOOH is the formula of steariq' acid and CnHaa is thealkyl residue of said acid.

As stated, many of the ketones which we use are. new materials. In ourcopending applications we have described and claimed them as such. Inour copending application Serial Number tinent lubricating oil. 17,873;filed April 23. 1935. we have claimed the Table 2 ren s Percent CloudPour 1 Viscosity added Mam point point index v "F. F.

.1 Flu lhe tadec lketone. 611 02 87.3 .5 r 38 10 511 62 87.3

. l Dibcnzoiuryl heptadecyl ketone 614 62 86. 7

.5 44 20' 638 01 74.8 1.0 do 524 01 78.6 .1 p-Bi henyl undecyl ketone510 02 86.1 .5 o a2 20 mo 02 88.7 v 1 Phenyl undecyl keton 51B 02 86. l

. 1 p-Ohlorphenyl undecyl ketone 507 62 88. 5

32 2%. iii s2 et 0 an e a so e no..

.5 :--do... .?.?.-.-i.u nuf 32 20 617 61.5 83.1 l p-Methoxyphenylundecyl ketone 617 01. 5 83. l

Control 42 20 518 62 86.2

mixed phenoxy phenyl alkyl ketones, in our co.- pending applicationSerial Number 17,874, filed April 23, 1935, we have claimed the mixeddiphenyl alkyl ketones, in our copending application Serial Number17,875, flied April 23, 1935, we have claimed the mixed furyl alkylketones, and in our application Serial Number 48,940, flied November 8,1935 as a division of Serial Number 17,875, we have claimed the'benzofuryl alkyl ketones.

Having thus described our invention, what we claim is:

1. A lubricating oil comprising a mineral lubricating oil containing asmall amount of the order of 0.1 to 1.0 percent, of a ketone having thestructural formula R-g-R wherein R is a closed ring radical and R' is analkyl radical having at least eleven carbon atoms.

2. A lubricating oil comprising a mineral lubricating oil containing asmall amount, of the order of 0.1 to 1.0 percent, of a ketone having thestruc tural formula wherein R is an aryl radical and R is an alkylradical having at least eleven carbon atoms.

3. A lubricating oil comprising a mineral lubricating oil containing asmall amount, of the order of 0.1 to 1.0 percent, of a ketone having thestructural formula wherein R is an aryl radical and R is the alkylresidue of a fatty acid containing at least twelve carbon atoms. a

4. A lubricating oil comprising a mineral lubricating oil containing asmall amount, of the order of 0.1 to 1.0 percent, 0! a ketone having thestruc' tural formula wherein R is a radical choan from the groupconsisting, of phenyl, naphthyl, diphenyl, anthracyl, fury], fluoryl,thiophenyl, carbozoyl and dibenrofury], and R is an alkyl residue of ahigher fatty acid containing at least twelv'e carbon atoms.

5. A lubricating oil comprising a mineral lubricating oil containing asmall amount, of the order of 0.1 to 1.0 percent, of a ketone having thestructural formula eleven carbon atoms.

"I. A lubricating oil comprising a mineral lubricating oil containing asmall amount, of the order of 0.1 to 1.0 percent, of a mixed anthracylalkyl ketone wherein the alkyl radical contains at least eleven carbonatoms.

8. The lubricating oil as in claim 6 wherein the ketone is a phenylheptadecyl ketone.

9. The lubricating oil as in claim 7 wherein the ketone is an anthracylheptadecyl ketone.

ANDERSON W. RALSTON. CARL W. CHRISTENSEN.

